Acne vulgaris is a chronic skin condition characterized mainly by comedones and papules. In severe cases, inflammation, pustules, cysts a scarring may occur. Acne occurs most often in adolescence, but may also occur in prepubertal children and in older persons. Acne vulgaris has its origin in the pilosebaceous units in the dermis, i.e., the hair follicles and associated sebaceous glands. Acne generally arises from an increase in androgen levels arising from an increasing influx in circulatory testosterone. This in turn causes the sebaceous glands to increase in size and activity, producing larger amounts of sebum and increased keratinization of the follicular walls, which blocks the sebum flow, dilating the follicle and entrapping sebum and cellular debris.
Control of acne is achieved by a combination of personal hygiene (including skin cleansing and dietary control) and the use of therapeutic agents. A prominent component of a regiment for controlling acne is the removal of excess sebum from the skin by thorough daily washing and the avoidance of topically applied fats and oils.
Therapeutic agents for acne and acneiform conditions are classified in three groups--(a) systemic and topical antibiotics, (b) peeling agents, and (c) retinoids. Systemic and topical antibiotics include tetracycline, erythromycin, minocycline, and clindamycin, but use of these agents is often accompanied by drug side effects, the development of resistance, and changes in the normal microbial flora. Peeling agents include benzoyl peroxide and salicylic acid, which unfortunately at times act as irritants or mutagens, particularly when combined with sun exposure. Retinoids include tretinoin (vitamin A or retinoic acid), which is applied topically to inhibit follicular keratinization, and isotretinoin (13-cis-retinoic acid), which is applied systemically to suppress sebaceous glands. Retinoids are often irritants and are not advised for individuals with sensitive skin. Retinoids can also be phototoxic, and they can induce thin and easily bruisable, fragile skin.